2001 came out in 1968; I was in eighth grade and living in Japan. Over the next year, I went to see the movie at least 14 times, including losing the chance at a girl friend over it (I took her to the movie, then spent the remainder of the date trying to explain the movie, and that was our last date). To steal an old 7-UP ad line, 2001 was the un-movie, which is one reason why, when 2010 was made a generation later, it was much more of the traditional plot and archetypal characters that movie audiences have learned to expect. I will occasionally watch it now, but more for nostalgia than fascination, since so much of the techniques and technology in the movie is outdated. I used to be a big fan of 2001. I still enjoy the special effects which still look great. I like the actors and all the stuff with H.A.L., which is classic. The soundtrack album helped get me into classical music. However, these days I see the whole evolution concept of the movie as rather over the top. The fetus floating in space representing the 'birth of the superman' strikes me as ridiculous now.
IMO, the great Kubrick film is Barry Lyndon.